Fuel system for an internal combustion engine

An internal combustion engine comprising a fuel system, in turn, comprising:

• a low-pressure circuit comprising at least one fuel tank;
• at least one low-pressure fuel pump;
• a first fuel filter and a second fuel filter which is arranged downstream of the first fuel pump;
• and
• a high-pressure circuit comprising a high-pressure fuel pump, wherein the high-pressure fuel pump comprises:
• means to suck fuel from the low-pressure circuit, and in case of failure in any of the at least one low-pressure fuel pumps, the high-pressure fuel pump is arranged to suck fuel from the low-pressure circuit and the fuel is arranged to by-pass the at least one low-pressure fuel pump via at least one by-pass pipe comprising a check valve that prevents the flow of fuel back to the fuel tank.

A vehicle comprising:

• an internal combustion engine;
• and
• a fuel system, in turn, comprising:
• a low-pressure circuit comprising at least one fuel tank;
• at least one low-pressure fuel pump;
• a first fuel filter and a second fuel filter which is arranged downstream of the first fuel pump;
• and
• a high-pressure circuit comprising a high-pressure fuel pump, wherein the high-pressure fuel pump comprises:
• means to suck fuel from the low-pressure circuit, and in case of failure in any of the at least one low-pressure fuel pumps, the high-pressure fuel pump is arranged to suck fuel from the low-pressure circuit and the fuel is arranged to by-pass the at least one low-pressure fuel pump via at least one by-pass pipe comprising a check valve that prevents the flow of fuel back to the fuel tank.

A method of operating the fuel system comprising:

• a low-pressure circuit comprising at least one fuel tank;
• at least one low-pressure fuel pump;
• a first fuel filter and a second fuel filter which is arranged downstream of the first fuel pump;
• and a high-pressure circuit comprising a high-pressure fuel pump, wherein said method comprises:
• identifying the functionality of the at least one low-pressure pump in the fuel system;
• in the event of good functionality of the at least one low pressure fuel pump, the at least one low pressure fuel pump is arranged to supply fuel from the at least one fuel tank to the high pressure circuit by operating the at least one low pressure fuel pump with an electric motor;
• or
• in the event of an identified operational disturbance in the at least one low pressure fuel pump:
• turning off all low pressure fuel pumps;
• arranging the flow of fuel to by-pass the at least one low-pressure fuel pump via a by-pass pipe comprising a check valve that prevents the flow of fuel back to the at least one fuel tank;
• opening an electrically controllable inlet valve of the high pressure pump;
• and
• operating the high pressure pump to suck fuel upstream of the high pressure pump.